Glial cells, Connective tissue coverings & Synaptic types Flashcards
What are the different types of Glial Cells?
- ) Astrocytes
- ) Oligodendrocytes
- ) Microgilia
What is the role of Astrocytes?
Can be supportive as well as reparative cells
What is the role of Oligodendrocytes?
Mechanism of Myelination in the CNS
What is the role of Microglia?
Macrophage of the CNS
What cells are responible for the myelinating of cells in th eperipheral nervous system?
Schwann cells
Define Endoneurium
Connective tissue covering surrounding individual nerve axons
It is continous with the Pia Mater
Define Perineurium
Connective tissue covering that divides nerves into fascicles (bundles of axons)
Define Epineurium
Denser irregular connective tissue that surrounds entire nerve.
It is continuous with the Dura Mater
Define Mesoneurium
Loose connective tissue that surrounds entire nerve.
It allows independent movement without impingement
Name the 4 differnt types of synapses that we are concerned with?
- ) Axondendritic
- ) Axospinous
- ) Axosomatic
- ) Axoaxonic
What synaptic types are considered faciliatry aka excitatory?
- ) Axodendritic
- ) Axospinous
What synaptic type is considered inhibitory?
Axosomatic
Define a Axodendritic synapse
A presynaptic neuron synapsing along the dendritic spine of the postsynaptic neuron
Define a Axospinous synapse
A subdivision of an axodendritic synapse but more complex as it might have 2 or 3 synpases affiliated with it
Define a Axosomatic synapse
A presynaptic neuron synapsing on the cell body of the postsynaptic neuron
Define a Axoxonic synapse
A synapse occuring between the axon of a presynaptic neuron and the axon of the postsynaptic neuron
When a neurotransmitter occurs on a soma that membrane potential become more postive or negative?
Negative
When a neurotransmitter occurs on a dendritic spine that membrane potential becomes more positive or negative?
Positive
Define Presynaptic inhibition
Less Calcium in the terminal, less Nuerotransmitter released, resulting in smaller depolarization on the post synaptic cell
Define Presynaptic facilitation
More calcium into terminal end, more neurotransmitter released,
resulting in larger depolarization on post synaptic cell
Excitatory synapses cause what?
The membrane to depolarize, raising membrane potential because it is becoming less negative.
Result in easier Action Potential to occur
Inhibitory synapses cause what?
Cause the membrane to hyperpolarize, making the membrane potential more negative.
Results in making it harder for an AP to occur
